Hair-bleaching agents based on a peroxide oxidation agent, such as hydrogen peroxide, urea peroxide, melamine perhydrate, etc. are generally used for the bleaching of human hair. A disadvantage of these peroxide bleaching agents is that they have to be used in an alkaline medium. Aqueous ammonia is generally used to adjust the required pH value and at the same time accelerates the oxidative destruction of the particles of the hair pigment (melanosomes). However, a considerable disadvantage is the highly irritating effect which ammonia has on the skin and mucous membranes and the unpleasant odor of ammonia which cannot be masked even by perfuming. Thus it became desirable to replace ammonia by odorless alkalinization agents such as alkali metal hydroxides, magnesium oxide or by alkanolamines and to further accelerate the bleaching process in order to avoid the disadvantages of ammonia on the one hand and, on the other hand, to minimize the oxidative damage to the hair. The bleaching accelerators used must, furthermore, be toxicologically compatible.
Therefore, the task arose of providing new compositions for bleaching hair which are based on peroxide oxidation agents and ammonia-free alkalinization agents and which do not have the aforesaid disadvantages.